Ask anyone what makes a good ceiling fan and they will say “high speed” or “powerful motor.” Both answers are wrong. What actually delivers comfort is Cubic Feet per Minute (CFM) — the volume of air moved per unit time. And CFM is determined far more by blade geometry than by motor speed.
The CFM Equation
At first approximation, CFM scales with:
- Blade span (radius squared)
- Blade pitch angle
- RPM (linearly)
- Number of blades (sub-linearly, due to interference)
This means doubling the blade span quadruples theoretical air delivery. But you cannot just scale a fan blade linearly — the aerodynamic profile changes, tip vortex losses increase, and you run into structural frequency problems.
What We Optimised
Entlar blades are pitched at 14.5° — steeper than the industry-standard 10–12°. At this angle, our fans deliver 18% more CFM at equivalent RPM versus typical market blades of similar span.
The tradeoff is torque requirement. Steeper pitch demands more torque at startup and at low speeds. This is precisely why our custom BLDC controller with full FOC is essential — a standard triac-dimmed induction motor simply cannot provide the flat torque curve needed to drive our blade profile efficiently below 100 RPM.
The Comfort Factor
Raw CFM is not the whole story. Air velocity gradient — how the moving air feels on skin — matters enormously. We spent three months in our airflow test chamber mapping velocity profiles at 50 cm, 100 cm, and 150 cm below blade height.
Our blade design produces a wider, more uniform column of moving air with lower peak velocity — which translates to a sensation of consistent, gentle airflow rather than the harsh downdraft of a high-pitch, small-diameter fast fan.
This is what we mean when we say engineering-first.